The invention to which this application relates is to a power tool, powered by any suitable source but most typically via a main electric or battery supply, which is used in the removal of material from a surface of a typically wooden article. This type of product is most typically referred to as a planer and that is the term used herein.
The provision of powered planer tools is well known. Planers are used in wood working to plane or smooth an uneven surface and may also include the removal of paint layers. The planer includes a blade assembly including a blade holding cylinder which is rotated at high speed. As the planer is moved across the work surface, raised parts of the uneven surface are shaved by the rotating blades which protrude through an aperture in the planing surface of the planar, the planing surface of the planar contacting the work surface and acting as a level and guide.
In order to obtain a smooth finished surface, it is typically necessary for the user of the planer to exert some downward pressure on the tool in order to steady the tool and maintain the rotating blades in contact with the work surface. This can be particularly difficult if the surface being planed is somewhat uneven. Further, maintaining a constant pressure to the tool can be difficult, firstly due to the irregularities in the work surface, and secondly due to the position of the user relative to the tool.
Wood chips, shavings and other debris are produced by the blade and are typically deflected towards the right or left side of the planer by the high speed rotation of the blade assembly. This can result in the work surface being obscured, the wood shavings being deflected towards the user, or often the rotating blade cylinder can become jammed by wood shavings accumulating within the blade chamber of the assembly. Typically the cylinder is mounted within the planer body for rotation about an axis which lies perpendicularly to the direction of movement of the planing surface of the tool along the wood, in use. The cylinder has on its outer periphery at least one cutting blade and the cylinder is offset from the planing surface such that the blade protrudes periodically slightly through an aperture in the planing surface as the cylinder rotates. This therefore means that as the cylinder rotates and the planing surface is moved across the wooden surface, the blade cuts into and removes chips of the wood. Typically, the blade position is adjustable to allow alteration of the cut depth.
A problem with the conventional arrangement is that with the provision of one, or in some instances, two blades on the cylinder spaced 180 degrees apart, the size of chip removed and the spacing between the blades contacting the work piece surface, means that as the planer is moved along the surface a scalloping effect is created on the surface which does not provide the desired effect. Furthermore, removal of the large chips which are created can be difficult.
The rotation of the cylinder is powered by a motor and conventionally the motor is mounted towards the rear of the cylinder. The front end of the planer is that which is at the front of the planer as it is moved along the wood surface. Conventionally it has been believed that to allow the most efficient positioning and drive of the cylinder the motor should be provided at the rear. However the positioning of the motor at the rear of the cylinder creates a problem with respect to the removal of the chips of wood and other debris created by the cutting action of the blade on the cylinder. The problem is that because of the motor position, the chips cannot easily be discarded from the rear of the planer which would be the natural flow of the same and so, instead, relatively complex chip removal channels are required to be formed in the housing along which the chips and debris are required to pass prior to leaving the planer housing and which typically are required to be fan assisted. The complexity of the channels can mean that the same are extremely prone to blockage by the chips which, in turn, prevents use or efficient use of the planer. Furthermore, to accommodate the removal channels, the housing can be required to be increased in size and may also cause the chips and debris to exit the housing at a location and/or side of the housing which is inconvenient to the user.
This problem has previously been recognized and at least one patent, EP0563350 attempts to provide a solution by improving the chip removal paths. In this patent, the motor is still mounted to the rear of the blade cylinder and so it is not possible to move the channels past the drive means motor as it will increase the width of the planer body. Instead, the patent suggests the provision of two channels leading from the cylinder, one passing along a first side of the body and the other passing along the opposing side of the body. The two channels each lead to an opening the user can control via a valve which of the channels is opened to allow the flow of the chips and debris, with the same leaving the planer body towards the front of the planer at a position in front of the blade cylinder. This complex channel arrangement requires the chips and debris to pass along a relatively long distance and in a direction which is required to be fan assisted as it is against the natural direction in which the chips and debris would flow having been removed from the wooden surface.
The aim of the present invention is to provide a planer which is powered and which has significant advantage to the user in terms of usage, in the removal of chips from the wooden surface and also in the removal of debris from the planer.